import Vue from 'vue'
const Mask = Vue.extend(require('./loading.vue').default)

function getStyle(element, styleName) {
  if (!element || !styleName) { return }
  styleName = styleName == 'float'
    ? 'cssFloat'
    : styleName
  try {
    var computed = document.defaultView.getComputedStyle(element, '')
    return element.style[styleName] || computed ? computed[styleName] : null
  } catch (error) {
    return element.style[styleName]
  }
}

const toggleLoading = (el, binding) => {
  if (binding.value) {
    Vue.nextTick(() => {
      if (binding.modifiers.fullscreen) {
        el.originalPosition = getStyle(document.body, 'position')
        el.originalOverflow = getStyle(document.body, 'overflow')

        el.mask.classList.add('is-fullscreen')
        insertDom(document.body, el, binding)
      } else {
        el.mask.classList.remove('is-fullscreen')

        if (binding.modifiers.body) {
          el.originalPosition = getStyle(document.body, 'position');

          ['top', 'left'].forEach(property => {
            const scroll = property === 'top' ? 'scrollTop' : 'scrollLeft'
            el.maskStyle[property] = el.getBoundingClientRect()[property] + document.body[scroll] + document.documentElement[scroll] + 'px'
          });
          ['height', 'width'].forEach(property => {
            el.maskStyle[property] = el.getBoundingClientRect()[property] + 'px'
          })

          insertDom(document.body, el, binding)
        } else {
          el.originalPosition = getStyle(el, 'position')
          insertDom(el, el, binding)
        }
      }
    })
  } else {
    if (el.domVisible) {
      el.instance.$on('after-leave', _ => {
        el.domVisible = false
        if (binding.modifiers.fullscreen && el.originalOverflow !== 'hidden') {
          document.body.style.overflow = el.originalOverflow
        }
        if (binding.modifiers.fullscreen || binding.modifiers.body) {
          document.body.style.position = el.originalPosition
        } else {
          el.style.position = el.originalPosition
        }
      })
      el.instance.visible = false
    }
  }
}

const insertDom = (parent, el, binding) => {
  if (!el.domVisible && getStyle(el, 'display') !== 'none' && getStyle(el, 'visibility') !== 'hidden') {
    Object.keys(el.maskStyle).forEach(property => {
      el.mask.style[property] = el.maskStyle[property]
    })

    if (el.originalPosition !== 'absolute' && el.originalPosition !== 'fixed') {
      parent.style.position = 'relative'
    }
    if (binding.modifiers.fullscreen && binding.modifiers.lock) {
      parent.style.overflow = 'hidden'
    }
    el.domVisible = true

    parent.appendChild(el.mask)
    Vue.nextTick(() => {
      el.instance.visible = true
    })
    el.domInserted = true
  }
}

Vue.directive('cusLoading', {
  bind: function (el, binding) {
    const mask = new Mask({
      el: document.createElement('div'),
      data: {
        text: el.getAttribute('element-loading-text'),
        fullscreen: !!binding.modifiers.fullscreen
      }
    })

    el.instance = mask
    el.mask = mask.$el
    el.maskStyle = {}

    toggleLoading(el, binding)
  },

  update: function (el, binding) {
    el.instance.setText(el.getAttribute('element-loading-text'))
    if (binding.oldValue !== binding.value) {
      toggleLoading(el, binding)
    }
  },

  unbind: function (el, binding) {
    if (el.domInserted) {
      if (binding.modifiers.fullscreen || binding.modifiers.body) {
        document.body.removeChild(el.mask)
      } else {
        el.mask &&
          el.mask.parentNode &&
          el.mask.parentNode.removeChild(el.mask)
      }
    }
  }
})
